fin also of Pseudorca is placed about the middle of the back, but in its height it
approaches more to the high dorsal of Orca than to the low dorsal of Globicephalus.
Pseudorca also, in the fewernumber of its vertebrae, 50, departs even more from this
form than does Orca, and in its lower spinous processes and in the union of its first
six cervical vertebrae, it differs considerably from this genus. The pectoral limb of
Pseudorca is narrow like the anterior extremity of Globicephalus and Gramptis,
but is proportionally very much shorter and smaller. I t is, however, very different
from that of Orcella, which is situated further away from the head, and is considerably
broader and more powerful. The scapula of Orcella in its great length and in
the curvature of its glenoid and acromial borders approaches more to the scapula of
Pseudorca than to the scapula of either Orca or Globicephalus, but it is distinct from
any of them. Its humerus, radius, and ulna are much longer than in Pseudorca,
and its manus is perfectly distinct from the narrow manus of the latter, in which the
fingers, especially the second and third, are close together, giving rise to a narrow
flipper, whereas in Orcella, they are along with the other fingers expanded and
widely apart, producing a moderately broad fin. In Orcella the phalanges are
broader than long, in Pseudorca longer than broad. The skulls also of these two
forms differ as much from each other as they do from Globicephalus and Grampus
respectively, and as do the two latter from each other ; indeed the skull of Orcella,
taken in all its features, has a closer resemblance to the skull of Grampus than to
the skull of Pseudorca.
The skull is distinguished from that of Globicephalus by its much less laterally
extended premaxi 11 aries and its vertebral column, by the union of only two of its
cervical vertebrae, an event which probably takes place after uterine life by anchylosis
of two previously existing segments, whereas, in Globicephalus, all the cervical
vertebrae are anchylosed or rather form one single bone as they originally formed
one single cartilage. I have also referred to other structural differences that exist
between the vertebral columns of Globicephalus and Orcella, more especially to the
differences in proportion between the transverse and spinous processes.
Erom such considerations as these, and viewing the structure of Orcella as a
whole contrasted with that of each of the already named genera, to each of which
it presents certain features of resemblance, associated, however, with marked dissimilarities,
it is evident that Orcella presents an assemblage of characters which
remove it from any of these genera and entitle it to generic rank. These characters
may be expressed as follows :—
Head globular ; dorsal fin low, situated behind the middle of the body ; pectoral
fins oval, about one-sixth the length of the animal. Teeth conical, larger and
fewer in the lower than in the upper jaw ; 13 to 17 teeth in upper and 12 to 14
teeth in the lower jaw. Skull beaked ; beak broad at the base, anteriorly pointed ;
premaxillary not much laterally dilated, bearing one tooth ; vertebrae 62 to 63 ; first
two cervical vertebrae anchylosed. Lumbar transverse processes moderately long ;
yertebral ribs 12 to 13, with one to two free ribs. Pelvic bones opposite 35th and
36th vertebrae.
Genus P l a t a n i s t a , Cuvier.
P l a t a n is t a g a n g e t ic a , Lebeck. , Plates XXV, &c.
Delphinus gangeticus, Lebeck, Der Gesellschaft Naturf. Freunde zu Berlin, 1801, vol. iii., pp. 280-282,
pi. 2 ; Roxburgh, Asiatic Res. vol. vii. 1801, pp. 170-174, pi. 5 ; Home, Phil. Trans. 1818, pp
417-419, pi. 21.
Delphinus rostralus, Shaw, Geni. Zool., voi ii., pt. 2,.1801, p. 514 ; Blainville, Nouv. Diet. d'Hist. Nat.
Appi. 1816-19, 2nd ed. Dauphin.
Delphinus shaioensis, Blainville, Nouv. Diet. cFHist. Nat. Appi. 1816-19, 2nd ed. Dauphin. •
Platanista gangetica, Cuvier, Rech. Oss. Foss., nouv. éd., Paris, vol. v. pt. 1, pp. 279-280, and pi. 22,
figs. 8 to 10.pl. 28, fig. 19; Lesson, Compiè. CEuv. Buffon, Cét. 1884* p. 215, Atlas pi. 8,
fig. 8; Gray & Hardw. 111. Ind. Zool. 1880-84, pts. xv. & xvi., pi. 4 ; Cuvier, Hist. Nat. Gét.
1836, pi. 8 fig. 2 ; Jardine, Nat. Lib. vol. vi. Mamm. 1887, pi. 28; M'Clelland, Cal. Journ.
Nat. Hist. vol. i. 1841, p. 425; Owen, Odont. 1840-45, p. 449; Gray, Cat. B. M. Cet. 1850,
p. 187 ; Cat. Seals, Whales, 1866, p. 223 ; Eschricht, Danske Vid. Selsk. Skr., 5te R. Bd. ii.
1851, pp. 847-887, 8 Pis.; Ann. and Mag. Nat.. Hist. vol. ix. 1852, 2nd ser., pp. 161-188,
pp. 279-298, pls.v. to vii.; Blyth, Ca,t. Mamm. As. Soc. Mus. 1863, p. 92; Flower, Trans. Zool.
Soc. (1866,) vol. vi. 1869, p. 87, et seq.
Platanistina gangetica, Gray, Voy. Erebus and Terror, 1846, Mamm. pp. 45, 46, pi. 7, fig. 2.
Eschricht in his admirable memoir on the structure of this remarkable type
of Cetacean fully summarised all that was known‘regarding it at the time he
wrote. Since then, Professor Elower has described many of the important features
of its osteology and greatly enlarged our knowledge regarding its affinities.
Eschricht considered that the figure of a female drawn under Reinhardt’s
direction was a faithful representation of the animal, and that “ the skill of the
draftsman, and, above all, the great experience of the naturalist, sufficiently guaranteed
the correctness of the delineation.” He has also stated that the accuracy of
the drawing was still further corroborated by the close correspondence of its proportions
with the skeleton of the self-same individual. There can be no doubt but
that this drawing which was reproduced by Eschricht, was, as a whole, a considerable
improvement on the representations of the animal given by Lebeck, Roxburgh,
Lesson, E. Cuvier, Sir William Jardine, and Gray, but it cannot be overlooked that
it erred in some important details. In Roxburgh’s figure of a male, the artist has
attempted to show the prominence of the head before the blow-hole, and he has given
the approximate position of the pectorals, in both of which features Eschricht’s
figure is at fault. As, therefore, a faithful delineation was a desideratum, I haye
reproduced a photograph of a female dolphin (Plate XXV).. A comparison of
this plate with-Eschriclit’s will show that the latter fails to represent the constriction
of the neck, the undulating outlines of the back and belly, the bulging character of
the head and the proper position of the pectoral fins. The constriction of the neck
is a marked feature of this Cetacean, and was to be looked for from the character
of the cervical vertebrae. Eschricht justly doubted the accuracy of Reinhardt’s
drawing on two points, viz., the positions of the eye and ear, which he considered
were placed too far above the angle of the mouth.
e 3